Apparatus for the magnetic separation of materials



Jam.V 4, 1944;` asi FQLLCWILL FAL 2,338,501 f vAPPARATUSVFORMAGNETIC SEPARATION 0F MATERIALS ,y Filed June'z', 1940' Y 2 sheets-'sheet 1` .13.11.45 1944. r `B 5, FOL 0W|| L ETAL- v 2,338,501

' APPARATUS WrjYoR MAGNEMCJSEPARATION 0F MATERIALSl Filed June l25,y 1940 2 Sheets-Sheet y1 -zin www lllllHll Patented Jan. 4, 1944 APPARATUS FOR THE MAGNETIC SEPARA- TION OF MATERIALS Bemis S. Followll, Riverside, and Allan R. Mac- Lagan, Western Springs, Ill., assignors to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application June 25, 1940, Serial No. 342,198

3 Claims. .(Cl. 209-223) This invention relates to apparatus for the magnetic separation of materials.

In certain types of electrical apparatus, such as communication equipment, it is customary to use small contact members made of precious metal. Gold, silver, platinum, palladium, iridium, and alloys of these metals, have been used for this purpose. The particular metal or alloy used in each instance depends upon individual service requirements and consequently a single installation often contains contacts made of a variety of metals and alloys. Whenever any of this .equipment is withdrawn from service, it is, of course, desirable to recover the precious metals therefrom. Accordingly, allv contacts are removed from discarded apparatus and accumulated for reclamation. The usual accumulation includes contacts of assorted sizes and shapes and a variety of compositions.

Reuse of these contacts, or any eifective reclamation thereof,.require s `segregation vof the contacts into their constituent met-al or alloy groups.

It is impossible to sortthese contacts lby Avisual .4 inspection,4 because of'their similarity of appear- 1 .anceyand ithas-'nt been considered practical .to

separate them magnetically, '1becauseeof: the very,

slight spread between the magnetic susceptibility of the metals and alloys of which the contacts are made. Previously, these contacts have heenreclaimed by chemical methods, which are slow `vei, platinumgpalladium, iridium, and their al' a loys, from a mixture of such articles.

In accordance with' onel embodiment ofthe invention, an apparatus is providediforfsorting ta-ken ,on the line 8 6.

belt bed are a second pair of spaced pole pieces mounted in the magnetic circuit'. The belt passes over one-.of these pole pieces, ch'anglng its" travel to a downwardly direction, and below this pole piece is a splitter blade for separating the alloy contacts, which fall from the beltat the end of its horizontal travel, from th'eplatinum contacts, which are held against the belt, by the magnetic field set up by the energized pole pieces, during travel of the belt around the pole surface.

Following is a more complete description of the invention, taken in conjunction with the appended drawings, in which Fig. 1 is a front elevation,-partly -in section,l

of a magnetic separating apparatus embodying certain features of the invention;

Fig. 2 is an enlarged view, in section, lof a porl tion of the apparatus shown in Fig. 1;

` Fig. 3 is a sectional view of Fig. 2, taken 'on the'-v i ,other portion of the apparatus shown in Fig. l,

and

Fig. 6 is an enlarged sectional view of Fig. 5,

` The"generalfarrangement of the apparatus is shown in Fig. 1"." It 'comprises a rigid base I0,

preferably made of metal, and three vertical legsextending from the base, on which the apparatus is mounted. One of these legs Il carries av feeding and driving mechanism and the remaina mixture' of contacts, including contacts madef.

of palladium, platinum, and gold-silver-platinum alloy. The apparatus comprises aA continuous moving belt on a horizontal bed onto which the contacts are deposited from a hopper andv then carried between a pair of spaced pole pieces mounted in a magnetic circuit energized 'by electrical coils. Positioned between the belt and the upper pole piece is a rotating disc of non-magnetic material having projections on its under face against which the palladium contacts are attracted and held by magnetic force, movedby the disc out of the magnetic eld, and dropped into a container. At the end of the horizontal ing legs i2 and i3 carrying the magnetic separating equipment. A continuous belt i4, supported on idler pulleys i6 and a belt driving pulley I8, extends through the feeding and separating mechanisms. The continuous belt is made of exible, non-magnetic material, preferably muslin, cotton or other textile. The belt must be ber solution -to prevent unravelling.

ing 25 on the leg Il. The drive shaft is connect-V ed to a suitable motor (not shown).

Mounted on a bracket 98, extending from the upper portion of the leg i I, is an open top hopper' 26 formed ofnon-magnetic sheet metal which contains the mixed contacts. The bottom of.

v ing pulley shaft I V(i To'accurately' position the belt below the brush. "andthus 'establish the maximum sized contact fthat the belt is supported on an adjustablethe contact containing portion of the hopper is formed by a rotating feed roller 21 of non-magnetic material (Figs. 2 and 3). This roller is mounted just above the belt and it has a series of indentatons 28 in its peripheral surface, each dimensioned to receive and deliver a suitable volume o contacts. Inside the hopper, extending over the roller, is a baiiie I5 to prevent the contacts from packing against the roller surface. The roller is supported on a shaft 29 which is rotatably mounted in the hopper wall. On this shaft is a sprocket 30 connected by a chain 3l to a sprocket 32 on the belt driving pulley shaft I9. Thus, as the belt pulley is driven to move the belt through the apparatus, the feed roller is also rotated by its chain to feed the contacts onto the moving belt in spaced arrangement.

To remove oversize contacts from the belt before they can enter the separator, a rotating cylindrical brush 33 is positioned a ixed distance above the belt. The brush is supported on one end of a shaft 34 which is rotatably mounted in a bearing 35 secured to a bracket 36 on the leg Il. The shaft andbrush arev rotated by means of a. belt 31 running from a pulley 33 on the brush shaft to a pulley 35 on the belt drivov'er idler pulleys 40 and 4i.

brush, this portion of plate 62 mounted on the bracket 3E. The lower surface of the brush is parallel to the plane of the belt and the brush shaft is positioned at an angle of about 30 to the longitudinal axis of the belt. Thus, whenever an oversized contact is deposited on the belt by the feed roller, it is engaged by will pass under the 'the brush and swept into a container 43 positioned below the belt on the bracket 36.

As above stated, the separating equipment, or the magnetic circuit, is mounted on the legs l2 and I3, which arise from the base l (Fig. 1). These legs are both made of non-magnetic material, such as brass or bronze. Positioned between these legs is a lower coil 45, having a winding 46 of many turns of wire on a core t1 between coil heads 48 of non-magnetic material, such as wood or fibre.

The core is made of high purity iron and has a large cross section. Tightly secured to one end of the core (left end in the drawings) i-s a lower front pole piece G of high purity iron which is also firmly secured to the leg l2. To provide s. close fit between the pole piece and the core, the end of the core is machined to a ilat surface and positioned in a machined recess in the pole piece. These members are joined with heavy bolts 51 which fpass through clearance holes in the pole piece and are threaded into the Similarly mounted on the other end of bolts 52 is a lower rear pole piece core. the core with 53 of high purity iron, the non-magnetic leg extend upwardly from ends near the belt.

Secured to the front lower pole piece is anupper coil supporting plate 54 and another" upper coil supporting plate 55 is secured -to the rear lower pole piece. These plates are made of nonmagnetic material` such as brass or bronze.

Between these plates is an upper coil 56 that is similar in general `construction to the lower coil, with a wire winding 51 on a pure iron core 58 between non-magnetic heads 59. Secured to one end of this core (the left end as viewed in the core with. their vupper the drawings) with bolts 60 in a front upper pole piece 6l of high purity iron and-secured to thev other end of the core with bolts 62 is a rear upper pole piece 63 of the same material. These upper pole pieces are mounted in the same manner as the lower pole pieces with the machined ends of the cores positioned in recesses in the pole pieces and the bolts drawn up tightly to provide good magnetic contact between cores and their pole pieces. Both upper pole pieces extend downwardly from the core and each terminates near the belt in alignment with a lower pole piece.

The cores in both coils pass through openings in the non-magnetic coil supporting plates and the plates are secured to all tour pole pieces with screws to provide a rigid structure.

The two coils are connected in series to a suitable direct current source (not shown), to energize the pole pieces and establish a magnetic held in the gap between each pair of pole pieces.

In the supporting plate 54 is an opening 6.4 and in the plate 55 is an opening 65, through which the belt passes between each pair of pole whichis also secured to v i3.' Both lower po'ie pieces disc are a series of radial cleats 80 or projections pieces. Suspended between these plates and aligned with the plate openings is a horizontal bed 6 for supporting the belt through this portion of the apparatus On top of the front lower pole piece 50 is a brass plate 61 on which the moving belt is supported (Fig. 2).

Secured with screws $8 to the lower end of the upper front pole piece 6| is a pole member 68. This pole member is triangular in cross section and its body portion is formed of a cobalt-iron alloy. A 50-50 cobalt and iron composition gives best results, but both constituents can var'y between 40% and 60%. end of one triangular face of the body portion of the member and welded thereto is a triangular projection 'lrof high purity iron (Fig. 4). The narrow end portion of this member is aligned with the center of the corresponding lower pole piece, and the projection extends beyond the belt and both the upper and lower pole pieces at right angles to the direction of belt travel.

Positioned abovethe belt in engagement with the lower end of the upper pole member lis a horizontal disc 11. This disc is supported on the end of a vertical shaft 12 which is rotatably mounted in a bearing 13 secured to the upper front pole piece 6i (Figs. 2 and 3) so that there is a portion oi the disc between the pole pieces and 'a portion of the disc outside of the pole end areas. This shaft and the disc are rotated through a pair of bevel gears 14 and a horizontal shaft 15 with a pulley 1S thereon by means of a belt 11 running from a pulley 18 on the hopper feed roller shaft 29 over an idler 18 on the bracket 36.

The disc is circular andmade lof:no'n'.-magnetic `material, preferably-phenol- 'bre, with a thin which are made of non-magnetic material, such as brass, and which project below the lower surface of the disc.

When the contacts are carried between the front pole pieces by the belt, those having suitable magnetic susceptibility, as determined by Extendingfrom the lower' piece 53 with -and has a wedge led below the disc on the lower iront pole piece.

At the end of the horizontal bed 66 (Fig. 1), is the lower rear pole piece 53 (Figs. 5 and 6).

- This pole piece has a concaved end surface tted into which is a tapered pole member 82 (Fig. 5) having a rounded end surface on which the belt is supported after it leaves the bed. The belt in passing over this rounded surface changes itsy travel from a horizontal to a downwardly direction. This pole member is also made oi the cobait-iron alloy comprising from 40% to 60% corounded end surface, or nose, of this member` are a plurality of spaced inserts 83 of non-magnetic material. 'These spaced inserts are paralleli to the direction oi belt travel and they extend through the end portion of the member, providing a series oi spaced magnetic poles under and across the width of the traveling belt. It is convenient to provide these inserts by cutting grooves across the'end of the pole member and lling the grooves with lead-tin solder, but other non-magnetic materials are satisfactory for this purpose.

Directly above the lower pole member, and spaced from the belt, is the upper rear pole piece 63. This upper pole piece has a lower end portion 85 which extends beyond and below the rounded nose on the lower pole member. Cut into the end surface of this upper pole piece is a recess 86 that is coextensive with the belt area at this point.

Secured to each side of the lower rear pole bolts 81 near the end ci the pole piece isplate 88 o! non-magnetic material, preferably aluminum.` The pole member 82 is anchored between these plates with bolts 89.

The aluminum plates also support an adjustable splitter 90 which extends between the plates shaped upper end portion positioned closely to and below the nose of the lower pole member. .The splitter is mounted on a pivotal shaft 9| supported in the aluminum plates, and iixed to the shaft on the outside oi one ci the plates is a graduated splitter adjusting arm 92. Below the splitter, and supported by the aluminum plates, are vtwo containers 83 and 94 separated by a partition 95 which projects into an opening 96 in the bottom end oi the splitter.

When the contacts not removed by the action of the front poles are carried by the belt over the end of-the lower pole member they are subjected to the action of the magnetic iields between therear pole pieces. The contacts that have the slightest magnetic susceptibility such as the goldsilver-platinum alloy contacts, fall ofi of the end oi the belt under gravity as soon as the belt begins its downward'travel. These contacts fall against the outer or right side of the splitter and are deilected into the container 93. Those contacts having relatively greater magnetic susceptibility, if paramagnetic such as the platinum contacts, are held'against the belt, by attraction to the lower pole member, for a period oi downward belt travel suihcient to carry them beyond the splitter. When these contacts reach a point where the magnetic field is sufficiently weak, they fall from the belt into the container 94. The splitter can be adjusted readily, by manipulation of the arm 92, to separate contacts'oi only slightly diierent magnetic characteristics, including both paramagnetic and diamagnetic materials.

An important feature of the apparatus is the combination of magnetic materials used in the magnetic circuit. The high purity iron used for the cores and pole pieces should have the following composition:

Per cent maximum Carbon .015 Silicon .003 Manganese .025 Phosphorous .004 Sulphur .025

Total impurities L .072

Iron Bal. As stated above, the end members on the two pole pieces are made of a cobalt-iron alloy containing from 40% to 60% of either metal.

As stated previously. the upper and lower coils have the same general construction. The outside diameters of these coils are equal but the upper coil is about twice as long and has about twice as many wire turns as the Vlower coil. The structure is compact and economical of power. Introduction of a direct current of 3 amperes and 110 volts in the coils produces a iiux density as high as 40,000 gauss in the pole tips and a iield of 15,000 oersteds in the gaps between the pole pieces. The spacing, composition and lcontour of the poles adapt the iield characteristics to the magnetic properties of the various contact compositions. The construction and operation of the apparatus insure accurate segregation'of each contact composition even though the contacts having that composition may vary widely in size and shape.

The apparatus has been described as used with a mixture of three compositions; namely, contacts made of platinum, palladium, and gold-silver-platinum alloy. This mixture is placed in the hopper and the contacts of each composition are rapidly accumulated by the apparatus in their individual containers. Ii a mixture contains more than three compositions, it is first passed through the apparatus to remove two of the compositions `from the mixture. In this operation one composition is extracted from the mixture by the rotating disc and another composition is removed at the rear pole pieces. The removed contacts are identied by their reactions to the magnetic fields, as determined by the apparatus setting. The residue, which is accumulated in either container 93 or 94, is then run through the apparat-us again after the apparatus setting has been changed. by adjustment of the current, pole pieces, or splitter to accomplish a separation of the remaining compositions. This operation is repeated, with any necessary changes in apparatus settings between successive operations, until all of the compositions are identiiled.` Thus, the apparatus is suitable ior rapidly; economically, and accurately sorting a varied mixture oi contacts, or other precious metal articles, into identiiied groups oi individual composition.

It will be apparent that some modications can be made in the specific embodiment of the invention described herein, and it is. therefore, to be understood that the invention is limited only by the scope of the appended claims.

' What is claimed is:

1. In an apparatus for magnetically separating materials from a mixture thereof, a moving belt l. pole piece having a body portion of triangular cross-section formed of an alloy comprising from 40% to 60% cobalt and the balance iron positioned with its narrow end surface adjacent to and spaced from the belt, and a triangular shaped member made of pure iron joined to the lower portion of one triangular end face of the body and extending therefrom with the lower surfaces of the body and member in alignment, a rotatably mounted disc of non-magnetic material positioned between the belt and the upper pole piece, means for energizing the circuit to establish a magnetic field between the pole pieces for attra/sting some of the material from the belt against the disc, and means for rotating the disc to remove the attracted materials from the magnetic field,

2. In an apparatus for-magnetically separating materials from a mixture thereof, a moving belt made of non-magnetic material for supporting the mixed materials, a magnetic circuit, a lower pole piece of high purity iron positioned in the circuit below the belt with its upper surface extending across the belt, an upper pole piece made of an alloy containing 40% to 60% cobalt and the balance iron in the magnetic circuit, said upper pole piece having'a triangular cross-section and being positioned with a narrow edge thereof adjacent to and extending across the belt coextensively with the upper surface of the lower pole piece, an auxiliary upper pole member of pure iron joined to one end surface of the upper pole piece and extending beyond the adjacent areas of theupper and lower pole pieces with its lower` end surface in alignment with the lower end surface of the upper pole piece, a rotatable disc of nonmagnetic material positioned between the belt and the upper pole piece, means for energizing made of non-magnetic material for supportingthe mixed materials, a magnetic circuit, a lower pole piece formed of pure iron in the circuit having its upper end surface extending across the lower surface of the belt, an upper pole piece formed of an alloy containing from 40% to 60% cobalt and balance iron secured to the lower end of the upper pole piece, said'upper pole piece having a triangular cross-section and being mounted with a narrow edge thereof extending across and spaced uniformly from the upper surface of the .belt coextensively with the upper surface of the lower pole piece, an auxiliary upper pole member made of pure iron magnetically connected to the lower end portion of one triangular end surface of the upper pole piece, said auxiliary pole member being tapered ln two directions and extending beyond the adjacent areas of the pole pieces and the belt with its bottom surface aligned' with the bottom surface of the upper pole piece, a rotatable disc of non-magnetic material positioned between the belt and the upper pole member, means for energizing the circuit to establish a magnetic field between the polepieces for raisingl a selected material from the belt against the disc, and means for rotating the disc to remove the selected material from the magnetic field,

BEMIS S. FOLLOWIIL. ALLAN R. MAcLAGAN.

' 'cmmmcus Aor comemos. Patent N .-.2.,558,5o1.v January l, 19th.@

sms s. renown.,- ET AL.

It is hereby certified that error appears in the printed specification ofthe above numbered patent requiring correction as follows: Page 1', seo'- ond column,j1ine 19, before view insert --plan; 1ine`21, before "View" I insert --elevational; line 25, before "section" insert --vertioa1..;

pgge 5, first column, line 6, strike out the syllable and words "halt and' the balance'substantially iron. 'In' the" and insert the same after "140% to 60% co" in line 18j and that the said Letters Patent should 'be read with this correction therein that the -same may conform to the record ofy the case in the Patent Office.

signed and sealed this 25thl day of Apr-11, A. D. 19ML.

Leslie Frazer.

(Seal) l Acting Commissioner of Patents. 

